The first 2012 gubernatorial primary contests are just over a month away, setting the stage for bruising battles in the fall in at least five states where four Democratic and one Republican governor are retiring.

But before the parties can focus on November, all eyes are on the mega-battle to recall GOP Gov. Scott Walker in Wisconsin, where 2010 Democratic gubernatorial nominee and former Wisconsin Rep. Tom Barrett entered the race Friday. The Democratic primary is on May 8, and the main event — the recall decision — is on June 5.

For the second month in a row, that puts the Badger State at the top of POLITICO’s rankings of the most competitive governors’ races in the country.

All the polling points to a razor-thin finish in the battle to remove Walker from office 17 months into his term. But Democrats still need to hash out who will attempt the historic feat. Barrett, mayor of Milwaukee, faces a primary against former Dane County executive Kathleen Falk, who has union backing and just last week pressured Barrett to back her.

One Democratic source tracking the race said Barrett was still mulling the contest when Falk went public with her nudging. “It’s personalities here. But that stunt annoyed him, so he’s out, then he’s in,” said the source.

Key questions: How disciplined will Democrats be during the one-month primary, and will their focus on each other lend Walker an opportunity to surf above the fray? For its part, the Walker campaign, which has run seven television ads since November, is getting plenty of aid from the Republican Governors Association, which began attacking Barrett on the air even before his entry. From Walker’s perspective, whoever appears opposite him on the ballot is secondary. “We’re going to be running against the public-sector unions driving the recall. It doesn’t really matter who it’s going to be,” said Walker spokesman Ciara Matthews.

Republican Bill Maloney ramped up his engagement of Gov. Earl Ray Tomblin, attempting to force the incumbent’s hand on white-hot issues the Democrat would otherwise avoid. He asked Tomblin to join a lawsuit against the Obama administration’s contraception rule and accused him of “enabling the federal government” by refusing to join thelegal challenge to the federal health care law. After comparing legislation to lure a natural gas cracker plant to the stateto “pulling down our pants,” he was just as quick to pin the blame on Tomblin when the company settled on Pennsylvania. It’s an aggressive posture that prompted Tomblin to email supporters: “Expect a tough race again this year. I wish I could tell you it’s going to be easy, but it’s not.”

Who won March: Maloney

No recent public polling

3. Washington (up 1 spot)

Democrat Jay Inslee’s campaign for outgoing Democratic Gov. Chris Gregoire’s seat must begin to confront a salient question: Can it possibly be successful with such an unwelcoming reception from the local media?

When Inslee decided to resign his House seat to redouble his efforts on the gubernatorial campaign, one local columnist lambasted him for quitting on his constituents. A weekly newspaper called The Stranger recently headlined a profile of the race: “Does Jay Inslee Exist?” Inslee’s uneven reaction to debate requests left him playing defense and in a public spat with one of the organizers. Some in the blogosphere even believe that it would be ill-advised for Inslee to say much about the health care law with the Supreme Court decision expected in June. GOP Attorney General Rob McKenna, who chose to join the lawsuit challenging the health care law, also has significant political capital riding on the high court’s decision. He believes the justices will strike down the individual mandate but keep intact the rest of the law. If the entire law is toppled, Inslee will have a hot-button issue that could help ignite a struggling campaign.

Who won March: McKenna

No recent public polling

4. North Carolina (down 2 spots)

Democrats believe that when his paid media campaign takes flight, Lt. Gov. Walter Dalton will leapfrog former Rep. Bob Etheridge before the May 8 primary for outgoing Democratic Gov. Bev Perdue’s seat. After publicly embracing Dalton at a Charlotte event at the start of the month, Health and Human Services Secretary Kathleen Sebelius walked back her full-throated endorsement. But Dalton might need more reinforcements. With just over a month to go, Etheridge has a 10-point primary lead among a Democratic electorate that remains largely undecided, according to Public Policy Polling. The muddle only benefits Republican Pat McCrory, whose candidacy is attracting fundraising assistance from GOP stars like Nikki Haley and Chris Christie as well as Jeb Bush next month. Even though the Republican’s approval ratings are soft, he’s easily outpacing all Democratic comers by double digits.

Much like McKenna, the Supreme Court’s health care ruling could adversely impact Democratic Attorney General Steve Bullock — but for the opposite reason. Bullock declined to join the multistate lawsuit against “Obamacare,” writing in April 2010 that he saw “no credible constitutional claim.” If the nation’s top justices disagree, it will be easy for Republicans to question the Democrat’s competence and judgment. The good news for the presumptive Democratic nominee is that he’s able to look toward the general election as the GOP navigates its colorful primary, which includes a deep-pocketed candidate who once offered advice on how to land a high-quality prostitute overseas.

Bullock selected Brig. Gen. John Walsh — who earned a Bronze Star in Iraq — as his running mate and continues to stack up a cash-on-hand advantage over GOP front-runner Rick Hill in the race for retiring Democratic Gov. Brian Schweitzer’s seat.

Who won March: Bullock

No recent public polling

6. New Hampshire (up 1 spot)

In what locals are describing as the most wide-open race in almost two decades, Republican Ovide Lamontagne is carrying a different torch. For his 2010 Senate bid, Lamontagne was the happy insurgent. He’s now lining up endorsements — like Rep. Charlie Bass and former Republican National Committee member Sean Mahoney — that fortify him as the establishment’s choice. Assuming Lamontagne’s outsider role is former state lawmaker Kevin Smith, who bracketed Lamontagne’s pickups with the support of former congressional candidate Jennifer Horn. Both contenders piled on Democrat Maggie Hassan for attempting to steer the conversation away from economic issues to the national contraception fight. But WMUR’s James Pindell responded to Hassan’s news conference lambasting Lamontagne and a “tea party Legislature’s” attacks on women’s health by calling it “her best day” of the germinating campaign. The contenders are fighting for outgoing Democratic Gov. John Lynch’s seat.

Who won March: Hassan

No recent public polling

7. Missouri (down 1 spot)

Just when observers thought the field was set, anti-cloning advocate Fred Sauer slipped under the radar and into the Republican primary. It’s still unknown how active a candidate Sauer will be, but the $400,000 he donated in 2006 to an anti-stem-cell research measure underscores his potential to self-fund his campaign. It’s just another complicating factor for Republican St. Louis packaging executive Dave Spence, who needs to run a perfect race to get within striking distance of Democratic Gov. Jay Nixon. The state unemployment rate has dropped to 7.4 percent, slipping to its lowest mark since late 2008.

Who won March: Nixon

No recent public polling

8. Indiana

After rankling some in his party for issuing a strong statement urging lawmakers to “move beyond this divisive issue” of right-to-work laws that make it harder to unionize, Democratic gubernatorial candidate John Gregg appears to have come home. The former state House speaker called for repeal of the law that made Indiana a right-to-work state. The issue highlights the tricky balancing act Gregg must perform in order to compete with GOP Rep. Mike Pence, who has thus far been rewarded with favorable headlines for staying trained on an economic agenda in the race for outgoing GOP Gov. Mitch Daniels’s seat.

Who won March: Pence

No recent public polling

CORRECTION: The first name of New Hampshire Gov. John Lynch was incorrect in a previous version of this story.